Glossy Ibis to be removed in 2013

Published on 30 January 2013

Each year the BBRC review the species/taxa that they assess to see if they should be removed from the BBRC list. A number of candidates were discussed at the 2012 BBRC AGM, which was held at Minsmere, Suffolk in March.  The outcome was that Glossy Ibis will be removed from the end of 2012.  All records from January 1st 2013 should now be sent to the relevant county recorder.

Obviously there has been a marked change in the status of Glossy Ibis in the last 10 years, and particularly since 2007 when the first annual influx of over 20 birds occurred, with a similar influx being repeated in every year since 2009. We know from the rings carried by some birds that they originated in Spain and this is likely to be the case for the majority.  The breeding population in Spain has become established since 1996 and has increased significantly since 2006 (Santoro et al 2010) expanding to southern France.  This species appears to be following the European breeding egret species on a range expansion resulting in a significant increase in occurrence in the UK. It is therefore considered that the increase will be sustained.  Glossy Ibis had not achieved the traditional thresholds to be considered for removal (e.g. more than 150 in the last 10 years, with 10 or more in eight of those years).  However, the occurrence of more than 100 records in five years, with 20 or more in at least four of those years indicates that the species is on course to comfortably exceed our traditional criterion. We therefore believe that the decision to remove the species is justified given the ease of identification and the relatively low rate of non-acceptance.

The other candidates considered included Lesser Scaup Aythya affinis, Citrine Wagtail Motacilla citreola and Olive-backed Pipit Anthus hodgsoni.  Lesser Scaup seems to occur in high numbers each year but many records are returning birds and the actual numbers do not meet our guideline criterion – the highest decade count is 117 for 1999 to 2008. Furthermore since 2008 reported numbers have decreased to an average of around 5 per year and this seems likely to continue in 2012.  The difficulties relating to the identification of females and young birds and the issue of separating adult males from lookalike hybrids remain real and these factors convinced us that it was sensible to retain Lesser Scaup on the BBRC list for now.

That leaves us with the two candidate passerines; Olive-backed Pipit & Citrine Wagtail.  With Citrine Wagtail the numbers do not reach the 150 in a decade threshold, but they have shown a steady increase and maybe a couple of more high-count years would see them leave the list.  Olive-backed Pipit is close to the 150 in a decade criterion and with another late-autumn influx having occurred in 2012, it is a likely candidate for removal. We will discuss the species again at our 2013 AGM, by when the 2012 numbers will be more accurately known.  We may make the decision to remove this species from the list from 1 January 2013 at the AGM, but will announce this after the meeting in March.

 

As well as looking at those that could be removed from the BBRC list we also look at possible additions, including some reinstated species.  Savi’s Warbler Locustella luscinioides represents a species that was reinstated to the list in 1999 following such a review and remains a genuinely rare bird in the UK, albeit showing a recent upsurge in occurrence.  One example that appears to show an occurrence pattern that would qualify as a BBRC rarity is Rustic Bunting Emberiza rustica.  A preliminary review of recent years supports the suspicion that numbers have declined since their peak in the 1990s, and have averaged less than 10 each year since it was removed from BBRC in 2006.  This reflects a declining population in Finland (www.atlas3.lintuatlas.fi/results/species/rustic%20bunting) and we will consider the status of this and other species at the 2013 AGM in Wales.  Birders are welcome to join us on the evening of Saturday 9th March of the AGM, when we will be gathering at RSPB Conwy Reserve.  More details will be available on the BBRC website (www.bbrc.org.uk) in due course.

References

Santoro, S, Máñez, M, Green, A.J, and Figuerola, J (2010) Formation and growth of a heronry in a managed wetland in Doñana, southwest Spain. Bird Study 57: 509-514.